On the Mainline Royal Scot repair I detailed in previous entry, it was necessary to fix the valve gear support bracket from one loco onto the other. It is held in place by 2 small pins, however one was broken off.  The plastic is quite soft and a bit soapy. I used  a new glue I'd just got, which worked very well with that material.

It's actually a liquid plastic welding compound which sets when exposed to ultra violet light.  There are various makes of this now which seems a very new glue. This one is called 5 second fix, which is probably the cheapest one.  The adhesive is in the pen body and is just squeezed out a drop at a time. Nothing happens until you shine the ultra violet torch at the other end on it.  It works very well on the plastic I tried it on. I've also used it to hold ez-line in place when used as biplane rigging. 

A friend in the US put me on to this, she makes dolls house accessories and needs to use very small spots of glue, her husband got her some of this, but hers came in a metal box with separate high quality torch and replaceable glue bottles.  That's Bondic brand, available here for around £20 a set.  The 5 second fix pen I bought is around £3 on e-bay etc. which is fine for a try out. Revell have started doing another pen version which is £10 for 2.

So my experiment worked, probably get a version with more adhesive next time, I suspect that for £3 there wont be too much liquid in the pen I got. But it does work, I suspect it may be similar to fluids used in 3d printing as it is u/v light that sets it. It effectively welds rather than glues.  Also it needs to be on the outside of whatever you are joining as it won't set without the light being shone on it.

Well worth a try for those tricky glue jobs.